Highly conductive carbon nanotube having bundle moieties with ultra-low bulk density and its manufacturing method

Abstract

The present invention relates to a highly conductive carbon nanotube having bundle moieties with ultra low apparent density less than 0.01 g/cc. More specifically, this invention relates to a highly conductive carbon nanotube prepared by following preparation steps of i) preparing the sphere shape of metal catalyst by spray pyrolysis of catalytic metal precursor solution including low molecular weight polymer, ii) synthesizing carbon nanotube using carbon source and obtained metal catalyst according to thermal chemical vapor deposition method; and iii) obtaining a highly conductive carbon nanotube having bundle moieties with ultra-low bulk apparent density.

What is claimed is: 
     
       1. A process for preparing a highly conductive carbon nanotube having bundle moieties with ultra-low bulk density comprising the steps of :
 i) obtaining a metal catalyst composition prepared by the following preparation steps comprising; a) dissolving 100 weight parts of metal catalyst particles represented by the following formula in water to obtain a solution, b) adding and mixing 0.1-20 weight parts of at least one low molecular weight polymer as an anti-aggregation agent to the solution obtained in step a) to yield a catalyst solution, c) spraying the catalyst solution into a high temperature reactor by a gas atomization method to obtain a gas atomized material, and d) preparing the metal catalyst composition with pyrolysis of the gas atomized material; 
 (Fe, Co, Ni) p (Al a Mg b Mn c ) q   
 wherein 
 p and q represent molar fraction of  p (Fe,Co,Ni) p  and (Al a Mg b Mn c ) q , 
 p+q=1, 0.3≦p≦0.8, 0.2≦q≦0.7, 
 a, b and c represent molar fraction of Al, Mg, Mn, respectively; 
 a+b+c=1, 0.1≦a≦0.8, 0.1≦b≦0.9, 0.01≦c≦0.2, and 
 ii) synthesizing a carbon nanotube having bundle moieties using a carbon source at 600-800° C. in the presence of the metal catalyst composition obtained in step i) according to a chemical vapor deposition method, 
 wherein the apparent density of the metal catalyst particles is 0.03-0.90g/cc and the apparent density of the highly conductive carbon nanotube having bundle moieties is 0.003-0.010g/cc, 
 wherein said at least one low molecular weight polymer has a weight average molecular weight(M w ) in the range of 100-10,000g/mol. 
 
     
     
       2. The process for preparing a highly conductive carbon nanotube having bundle moieties according to  claim 1 , wherein said at least one low molecular weight polymer is selected from ionic or non-ionic dispersing agents. 
     
     
       3. The process for preparing a highly conductive carbon nanotube having bundle moieties according to  claim 2 , wherein said at least one low molecular weight polymer is at least one selected from sodium dodecyl benzene sulfate(NaDDBS), sodium dodecyl sulfate(SDS), cetyl trimethyl ammonium chloride(CTAC) or dodecyl trimethyl ammonium bromide(DTAB). 
     
     
       4. The process for preparing a highly conductive carbon nanotube having bundle moieties according to  claim 2 , wherein said at least one low molecular weight polymer is at least one non-ionic dispersing agent comprising head part and tail part, wherein the head part is at least one aromatic hydrocarbon selected from benzene, naphthalene, acenaphthylene, acenaphtene, anthracene, phenanthrene, pyrene or benzanthracene, and the tail part is a polymer chain consisting of hydrophilic repeating units. 
     
     
       5. The process for preparing a highly conductive carbon nanotube having bundle moieties according to  claim 4 , wherein the hydrophilic repeating units are ethylene oxide or propylene oxide.